Blue Christmas?

  

Well, the waves were on the larger side today (10-12 foot west swell), but we picked a safe spot and went out for a little holiday tidepooling in the mid intertidal zone late in the day.  One of my favorite observations was this beautiful blue shrimp!  I'm not sure which species this is, but I couldn't resist sharing the photo.  [You can click on the image for a larger version.]

Against the grains

 

 

Okay, so this post is a follow-up to last night's photo.  This shrimp is a master of camouflage, but here are a couple of photos (above and below) where it might be a little easier to see them because they're on the surface of the sand.

 

 

We've learned the pair of white spots just in front of the tail (on the 5th abdominal segment) are consistent enough that you can use them to locate the shrimp and orient to its tail and head ends.  Sometimes the white spots are merged into the shape of a heart.

 

The shrimp's coloration is remarkable — they match the sizes and colors of the surrounding sand grains and shell pieces so well that even when the shrimp was right in front of us it was often hard to see it.  The next two photos are a little more challenging, but I'm guessing you'll find the shrimp!  (Hint: You can also look for the narrow white stripes on the legs.)

 

 

 

 

 

We think this beautiful shrimp is Crangon handi, although we had to look more closely at several features to work through the identification (and see note at bottom of this post).  Some of these characteristics are hard to see in the field, but because we've noticed there aren't many Crangon handi photos online, Eric made this really useful guide to point out some important features (see below). 

 

Note the shape of the antennal scale, the shape of the claw on the cheliped (fancy name for a leg that bears a claw), and the three tiny spines that flank each side of the very tip of the tail (telson):

 

 

Drawings modified from Kuris, A.M. and J.T. Carlton (1977). Description of a new species, Crangon handi, and new genus, Lissocrangon, of crangonid shrimps (Crustacea: Carida) from the California coast, with notes on adaptation in body shape and coloration.  Biological Bulletin 153: 540-559.

 

We found these shrimp in small patches of open sand between rocks in the intertidal zone.  Although the shrimp are so well camouflaged that we've probably walked by them many times without noticing them!

 

I can't help showing a few close-ups so you can appreciate how well they match the sand.  One of the anterior end (with two rounded pearly eyes), one of the tail, and a close-up of the pigment spots called chromatophores (there are also some actual sand grains on the shrimp):

 

 

 

 

 

 

 

P.S.  I showed a photo of Crangon handi from a more wave-exposed site back in June — see "Perfect match" on 23 June 2023.  Note that the larger color patches on that shrimp match the coarser grains on the outer coast.

 

P.P.S.  There are a few things about these shrimp that stray from the original description — e.g., we found them on finer-grained sand and their color patterning is finer.  However, we noticed a photo in Jensen's Crabs and Shrimps of the Pacific Coast (2014) that shows Crangon handi with similar patterning to the shrimps we photographed.  But if you have thoughts about this identification, let us know!  We're interested and open to looking further at any defining traits for this species.

 

Find the shrimp?

  

Can you find the shrimp?

More info tomorrow night!

Perfect match

 

 

What a cool shrimp!  Such amazing camouflage, matching all of the colors in the sand grains -- white, brown, gray, black, green, and orange.  Meet Crangon handi!  [You can click on the image for a larger version.]

 

The eyes of the shrimp are on the right side (two rounded brownish eyes); the body tapers back to the left; and the tail is on the far left side (look for two narrow white bands above the larger white sand grain).  [I'm calling it sand (≤2 mm), but it's possible it should be called gravel (≥3 mm).]

 

This species is known to inhabit gravelly tidepools, and lucky for us, one of the UC Davis Bio Boot Camp instructors spotted it this morning.  Thanks, Kaitai!

 

P.S.  If the species name sounds familiar, it's true this species was named in honor of Professor Cadet Hand, first director of the Bodega Marine Laboratory.

Disappearing act

  

One of the most impressive features of many animals in the intertidal zone is the way their color patterns match their surroundings.  It makes it challenging for visual predators to spot them.  And it also requires an observer to slow down and let their eyes and mind adjust to the setting in the tidepool.  (Maybe we need a new phrase ="slow tidepooling"?)

We thought it would be fun to show some examples.  Above is a chiton (perhaps Lepidozona radians) — note there are eight plates, but the middle four plates are orange, the front two plates near (head end) are flecked with brown and green, and the back two plates (tail end) are mottled.  These varied colors make it hard to identify this as a chiton at first.

Below is a small sculpin.  Check out the way the pink stripe running across its body matches the coralline algae patches on the rock.  And the other colors look like the surrounding rocks (grays and greens) and encrusting algae (deep maroon).  It also helps that sculpins often stay very still — the lack of movement makes it less likely that they'll catch your eye:

 

 

The camouflage abilities of octopus are well known — they can settle on a new substrate and blend in within seconds by adjusting pigment cells (chromatophores) in their skin.  Here's one looking a lot like a rock — but also note how well the arms/tentacles on either side of the body have a different color and pattern than the main portion of the body.  It's hard to make them out!  (If you look closely sometimes you can spot the suckers on the underside of the tentacles.)

 

 

And here's one more — an intriguing shrimp called a Deep-blade Shrimp (Spirontocaris prionota). (Hint: Look for the shrimp's eyes in the center of the photo.)  Not only do the colors of the shrimp match the coralline algae, but the shrimp also has small hairs (setae) that accumulate bits of debris that help it look "messy", making it less clear that this is a shrimp.

 

 

It takes some special attention to spot animals like this when they're so well camouflaged, but it's worth the extra time! 

ADDENDUM (31 December 2022) — P.S.  To make it easier to find the octopus, here's an edited photo showing the outline and main features:

 

 

Bright blue highlights

  

Eric had good luck with spotting interesting shrimp last night (25 November 2022).  Here's another one -- with red/maroon background colors and bright blue spots scattered across the abdominal segments.  We think this is probably a Heptacarpus species, but I'm not sure which one.

And here's an even closer view of those beautiful blue spots!

 

 

Fun to know these handsome shrimp are living along the Sonoma coast!

Blue galaxy

 

 

So cool!  Eric photographed this shrimp in the low intertidal zone tonight (25 November 2022).  We think it might be a species of Heptacarpus, possibly Heptacarpus brevirostris.  (But if you have more experience with shrimp and have a different opinion, please let us know.)

 

I love the blue-green background color and the bright blue spots!  Sometimes Heptacarpus brevirostris is called the Stout Coastal Shrimp, but this one made me think of a galaxy, so tonight I'm calling it the Blue Galaxy Shrimp.  :)

 

Thanks, Eric!

Visiting the cleaners

  

Looking around in the low intertidal zone in Monterey County this week, I peeked over a rock to see these striking striped shrimp.  Beautiful!

I kept scanning and found a handful of these shrimp in a tidepool.  This was my first view (below).  [Don't miss the smaller individual at the bottom.]

 

 

I'm not as familiar with many invertebrates that are more common in Southern California, but Eric helped me identify these as Red Rock Shrimp (Lysmata californica).  Typically they are found south of Point Conception, but there are recent records of them from San Luis Obispo, Monterey, Santa Cruz, and Pillar Point (between 2015-2021).  And there is an older record from Coos Bay, OR, from 1983 after a significant El Niño event.

These are fairly large shrimp — the largest individual I saw was ~7 cm (~3 inches) long.  They have a grayish translucent background color and bold red striping.  Another notable feature is the extremely long antennae.

 

 

An intriguing aspect of Red Rock Shrimp — they're cleaner shrimp!  Which means that they are often found in large aggregations and are known to have a mutualistic relationship with various fish and invertebrates that involves "cleaning" — the shrimp remove parasites and other material from their "clients" including moray eels, Garibaldi, and spiny lobster.

 

 

 

Most of the other species in this genus of cleaner shrimp (Lysmata spp.) are tropical.  I'm not sure how common Red Rock Shrimp are north of Point Conception right now, but if you happen to see one north of Santa Barbara it would be worth reporting your observation.  

Two more images for the record:

 

 

 

 

 

I felt fortunate to catch a glimpse of these beautiful shrimp and couldn't help wondering which animals might be stopping by next to visit the cleaners.

How to become invisible

If you're a resident shrimp in a tidepool filled with hungry sculpins, you might find it advantageous to be invisible.  So how do you become invisible?

Step 1: Become a color that matches things in the background of the tidepool, e.g., pink like coralline algae:

 

 

 

Step 2: Add highlights — spots and bands of different colors that show up in the background.  For example, white stripes that match the white tips of the coralline algae, and some darker reds that match the shadows:

 

 

 

 

Step 3: Make some of your body parts look like algae.  For example, you could make your head appendages, or the sides of your abdomen, or the tip of your tail look like the branches of coralline algae.  And you could hold your abdomen and tail in an upright position:

 

 

 

Step 4: Adapt your behavior to make it hard for a fish to spot you.  For example, stay very still, and only become more active at night.  (Shhhh...no shrimp here!)

 

 

 

Meet the incredible shrimp, Lebbeus lagunae!  Eric spotted this amazing shrimp while we were tidepooling during the exceptional low tide on 5 December 2021.  It was hard to believe what we were seeing at first.  It's a fantastic example of crypsis — avoiding detection by predators via use of colors and patterns and shapes that help to blend in with the background. 

The geographic distribution of this species is typically described as Baja California, Mexico to Monterey, California.  However, we are looking into a possible record from Mendocino County (thanks to Jim!). So this shrimp could be a primarily southern species that is rare here, or it might just be rarely seen here given that it's almost invisible and more active at night.

 

 

 

Many thanks to Eric for his excellent observation skills!  Now you can imagine these shrimp hiding among the coralline algae in the local tidepools.

Coastal colors

 

I need to learn more about shrimp.  There sure are some beauties along our coast!

 

Lavender eyes

We're back late again from doing surveys in the rocky intertidal zone, but here's one quick shot from tonight (25 November 2018). 

One time while I was searching for something else, I looked down to see these beautiful lavender eyes:

 

Such a wonderful shrimp!

Ultra Violet mystery

On 7 and 8 December 2017, I showed two mystery photos:

 

 

If you guessed that this is a type of crustacean (i.e., the group that contains crab, lobster, and shrimp, among other animals), you are correct.  So the next question is, what type of crustacean?

Here's another close-up, revealing a bit more. This animal was ~2.5 cm long.

 

Meet Betaeus harfordi!   This is a shrimp in a group that is sometimes referred to as "hooded shrimps."  In the second close-up (above), and in the photos below, you can see that the carapace extends up and over and slightly in front of the eyes.

Older summaries about this species describe it as dark purple, blue-black, or deep blue.  The first individual we photographed (above) showed strong purple coloration, but we also looked at a second individual that tended towards the blue side:

 

Here are the two together so you can compare the colors.  [The photographs below were taken outdoors in natural light, rather than indoors in the lab.]

 

Betaeus harfordi has an interesting life history.  This shrimp has an obligate association with abalone.  It lives in the mantle cavity of abalone along the West Coast (all eight species).

A shrimp leaves the shelter of the abalone to feed at night, but then returns to its host during the day.  (Interestingly, a shrimp can sense the presence and location of its abalone host chemically!) 

Here are two more photos.  Note the "hood" over the eyes and the interesting claws (with the movable portion of the claw at the bottom):

 

 

Many thanks to our colleagues who study abalone for sharing these fascinating symbiotic shrimp!

P.S.  The "harfordi" part of the scientific name refers to William G.W. Harford, director of the California Academy of Sciences from 1876-1886.

 

Deep-blade

Here's a fun mystery close-up — an extreme view taken through a microscope.  Can you guess what type of animal this might be?
 

 

I'll zoom out a bit more:

 

And now I'll show the entire animal, so be prepared for the answer below!  

First, a few more hints: This is a crustacean that can be found in the low rocky intertidal zone and subtidal areas, but it's relatively small and can be quite cryptic.  [In the photos above, the small, colorful patches are chromatophores which play a role in camouflage.] 

Hmmm.  On second thought, I've change my mind — here's one more close-up before I give the answer away.  (Although this photo will probably help a lot!)

 

Isn't that a spectacular tail?

Okay, now here's the entire animal:

 

Meet Spirontocaris prionota, commonly known as a Deep-blade Shrimp.  This is the first time we've encountered one on Bodega Head.  I was impressed with the details and colors when viewed under high magnification.

The "deep-blade" portion of the name refers to the distinctive rostrum — the portion of the carapace that projects forward in front of and above the eyes.  It's extremely narrow (like a knife), and impressively serrated above (see first two photos).

To orient you to this shrimp's anatomy, the next image shows the same photo with a few labels:

 

Apparently, not much is known about the biology of this species.  Here's one more image — a head-on view emphasizing how well camouflaged this shrimp would be among the rocks and sand.  And note some of the other intriguing features.  For example, what do they do with those small front appendages tipped with noticeable black spines?  Why do they have clusters of long setae (bristles) on their legs?

 

Red, white, and...Boom!

Tonight's post starts with a fun video.  Check out these wonderful sequences of a Twistclaw Pistol Shrimp (Alpheus clamator) that Eric filmed recently.  [If you receive this post via e-mail and can't see the video below, click on the title of the post above to go to the website.]

Watch for a variety of things in the video, e.g., the small chromatophores (like polka dots scattered across the body), the heart beating, the antennules flicking, the long hairs on the claws.  And note the two different types of claws, especially the larger, intriguing left claw:

pistol_shrimp_sanford from Jackie Sones on Vimeo.

Although Twistclaw Pistol Shrimp have now been recorded in Oregon, their distribution is generally more southern.  We've only found a few in the Bodega Bay area.

Pistol shrimp are also known as snapping shrimp.  So if you've heard of snapping shrimp, or even heard snapping shrimp yourself, this shrimp is a member of that group.

The common names refer to a remarkable ability (not revealed during the video).  The oversized claw is very unusual — instead of being used for crushing or tearing, it can produce a loud snapping sound and powerful shock waves that stun its prey! 

Although I'm not great with physics, here's a basic explanation of how it works.  At the tip of the claw there is a "plunger".  The "plunger" can be "cocked" — i.e., locked in an open position — but when released, the "plunger" hits a "socket" on the opposite side with such a powerful force that it creates an extreme high-velocity water jet (at ~60 mph!).  A bubble forms in the low pressure area in the wake of the water jet.  The bubble grows quickly, but then the high pressure surrounding it causes it to collapse on itself (also known as cavitation).  All of this happens so quickly that when the bubble collapses, it emits heat, light, and sound, and it creates a shock wave that emanates from the claw.  In addition to stunning prey, it's possible that pistol shrimp use the snapping sound for communication and defense of their burrows.

From the side, you'll notice that the large claw has an unusual shape.  Below are two pictures, one showing the entire animal, and the second a close-up of the claw:

 

 

(These are different individuals, but it's the same species.)

From the side views, it's hard to interpret what's going on, but it's a little easier with two views from above. The first shows the claw in the closed position:

 

And the second shows the same claw with the "plunger" in the "cocked" position:

 

A slightly different angle allows you to see both the "plunger" and the "socket".

It's an amazing design and an incredible behavior.  If you're lucky enough to find a pistol shrimp, listen carefully and take a close look at the claw!

P.S.  We thought this might be an appropriate topic for the holiday.  Happy Fourth of July!